The bottom line: Although there’s little overt discrimination — legislated or popular — against “sexual minorities,” as Japanese officialdom terms them, there’s also little support for recognizing or legalizing unions between same-sex couples.

Same-sex marriages aren’t legal in Japan, and few serious steps to legalize them have been taken yet. Japan doesn’t recognize civil unions between same-sex couples either.

One big obstacle to same-sex marriage is Article 24 of the Japanese constitution, which stipulates that “marriage shall be based on the mutual consent of both sexes.”

Since the Japanese constitution is notoriously tough and time-consuming to change, and indeed hasn’t been revised since it took effect in 1947, that barrier likely means a long road ahead for legalizing same-sex marriage — even if there was popular support to do so, says Masakazu Umemura, a lawyer specializing in marriage- and inheritance-related cases.

Mr. Uemura noted that the Japanese public hasn’t shown much interest in the issue, although a few lawyers are pushing for legalization, along with gay activists.

The conservative official stance on unions for same-sex couples isn’t a surprise. Japanese family law, which governs everything from marriages to name changes, is highly rigid — for heterosexuals as well as homosexuals. Japanese family law doesn’t permit married couples to have different surnames, for instance.

Japan’s ruling Liberal Democratic Party, which is chock full of traditionalists from Prime Minister Shinzo Abe on down, also has a dim view on gay marriage.

Rainbow Pride Ehime, an activist group for Lesbian, Gay, Bisexual or Transgendered people, conducted a multiple-choice survey of Japanese political parties’ stances on same-sex marriage right before the general election in December 2012. The LDP chose the response “Marriage should be between different sexes. Thus there is no need to adopt a legal marriage system” for gay couples.

Some smaller and less-traditional parties were more supportive. The Japan Restoration Party and the Social Democratic Party said they supported legalizing same-sex marriage, while the Communist Party was for an introduction of civil unions.

There are, however, a few signs that support is growing for gay marriage in recent years.

In 2009, Japan’s Justice Ministry said that it would start issuing documents sometimes needed by Japanese nationals who wanted to marry same-sex partners abroad.

Informally, there’s a fair amount of public acceptance of same-sex couples in Japan, though relatively few Japanese nationals choose to come out and agitate for change, compared to countries like the U.S.

At least one traditional Japanese temple also offers a marriage ceremony for gay couples. Shunkoin, a 420-year-old temple in Kyoto, started holding Buddhist wedding ceremonies for same-sex partners a couple of years ago, after some foreigners who visited the temple for zen meditation asked whether lesbian couples would be allowed to marry there. The temple’s deputy monk, Zenryu Kawakami, told JRT that he did some research, and found that Buddhist “sutra does not oppose it or approve it.” Mr. Kawakami has since wedded five lesbian couples–mostly foreigners. “Buddhist followers are often quite liberal,” Mr. Kawakami said.

“Unlike the U.S. and other countries, there is no religion-based discrimination or hatred of sexual minorities in Japan. However, there is insufficient knowledge and awareness,” said Patrick Linehan, the openly gay U.S. Consul General for Osaka, in a February interview with the Ehime Shimbun excerpted on the consulate’s Web site. Mr. Linehan, who married his spouse in 2007 in Canada, says the pair attend functions together as a couple — and are sometimes greeted with puzzlement, but not discrimination.

“When I first came to Japan 25 years ago, a Japanese person told me that there were no gay people in this country,” recalled Mr. Linehan in the interview. “Japan has also changed a lot.”

About Japan Real Time

Japan Real Time is a newsy, concise guide to what works, what doesn’t and why in the one-time poster child for Asian development, as it struggles to keep pace with faster-growing neighbors while competing with Europe for Michelin-rated restaurants. Drawing on the expertise of The Wall Street Journal and Dow Jones Newswires, the site provides an inside track on business, politics and lifestyle in Japan as it comes to terms with being overtaken by China as the world’s second-biggest economy. You can contact the editors at japanrealtime@wsj.com